The present invention relates to medical procedures and devices, more particularly to those devices used to infuse and remove fluids from the body of a patient during a surgical procedure.
Endoscopic/laproscopic surgical procedures have grown significantly in popularity over the years due to the fact that they are minimally invasive and the miniature, remotely-controlled surgical instruments used have improved. To allow such procedures to be undertaken, means are frequently required to distend the patient""s body cavity at the site of surgery to allow for surgical implement manipulation and visualization. Gasous or liquid insulflatants are used for this purpose depending upon the operation. Certain procedures also utilize a liquid insulflatant as a lavage for removing blood and excised tissue from the surgical site to maintain visibility and to clean the area. For example, in fibroid removal, the uterus is flooded with a clear liquid, e.g., isotonic saline solution, under sufficient pressure to separate the walls of the uterus to permit the surgical site to be viewed with an endoscope. After the uterine cavity has been distended by the liquid, a surgical tool such as an electrocautery tool or resectoscope, may be positioned within the uterus to remove the fibroids which are vaporized at its cutting surface. During the surgery, fluid flow out of the uterus is maintained and the severed tissue and electro surgical debris are removed from the uterus with the outflowing fluid. During procedures of this type, the amount of irrigating liquid present in the patient""s body must be closely controlled because excessive absorption thereof can be extremely detrimental to the patient. Accordingly, inflow to the body cavity must closely approximate outflow. In certain instances, a pressure differential is provided in order to maintain distension of the cavity. Many fluid management systems utilize a source of vacuum to control fluid outflow. Various methods have been proposed in the past to monitor the fluid inflow and outflow in surgical fluid management systems, but there is a continuing need for ever improved precision in the management of fluid flow in these applications. Accordingly, an object of the present invention is to provide for simpler, more accurate and more reliable fluid flow control during surgical procedures.
The problems and disadvantages associated with conventional techniques and devices for controlling the volume of surgical fluid present in a cavity of the body during surgery are overcome by the present invention which includes a fluid pump for pumping surgical fluid to the cavity via a conduit. A dampener is disposed between the pump and the cavity, the dampener receiving the fluid output of the pump and having a pressure sensitive volumetric capacity therefor such that variations in output volume of the pump are diminished by the dampener, the output of which is directed to the cavity. dr
For a better understanding of the present invention, reference is made to the following detailed description of an exemplary embodiment considered in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic diagram of a fluid management system as known in the prior art;
FIG. 2 is a schematic view of a fluid management system in accordance with the present invention;
FIG. 3 is a front perspective view of a flow dampener in accordance with the present invention;
FIG. 4 is a rear perspective view of the flow dampener of FIG. 3;
FIG. 5 is a cross-sectional view of the flow dampener of FIG. 3 taken along section lines Vxe2x80x94V and looking in the direction of the arrows;
FIG. 6 is a cross-sectional view of the flow dampener of FIG. 4 taken along section lines VIxe2x80x94VI and looking in the direction of the arrows;
FIG. 7 is a cross-sectional view of the flow dampener of FIG. 4 taken along section lines VIIxe2x80x94VII and looking in the direction of the arrows;
FIG. 8 is an end-on view of the cross-section of the flow dampener shown in FIG. 7;
FIG. 9 is a diagrammatic view of light transmitted through an empty tube and reflected from an adjacent reflective member;
FIG. 10 is a circuit diagram for an optical sensor in accordance with the present invention;
FIG. 11 is a perspective view of an optical fluid sensor in accordance with a second embodiment of the present invention;
FIGS. 12-14 are cross-section views of second, third and fourth embodiments of the flow dampener of the present invention;
FIG. 15 is a schematic diagram showing the relationship between elements in a vacuum control system in accordance with the present invention;
FIGS. 16 and 17 are schematic diagrams showing a spool valve in two different states of distributing and measuring vacuum in a fluid management system in accordance with the present invention; and
FIG. 18 is a graph of pressure vs. time exhibited by a fluid management system in accordance with the present invention.